Woven multi-layer fabrics for use with ballistic threats

ABSTRACT

A multi-layer woven fabric, including an upper woven layer having upper warp yarns and upper weft yarns that are interwoven together to form the upper woven layer. The cover factor of at least one of the layers is selected so as to inhibit penetration by non-ballistic threats.

PRIORITY OF INVENTION

This application is related and claims priority to U.S. ProvisionalApplication Ser. No. 62/117,733, filed on Feb. 18, 2015, the entirety ofwhich is incorporated herein by reference.

TECHNICAL FIELD

The embodiments herein relate to fabrics and in particular to wovenfabrics for use in ballistic applications.

INTRODUCTION

Woven fabrics are fabrics in which two or more distinct sets of yarnsare interwoven with each other to form the fabric. Typically, wovenfabrics include warp yarns that run lengthwise along the fabric and weftyarns that run across the length of the fabric, and which are interwovenwith and generally perpendicular to the warp yarns.

In some ballistic applications, it is desired that two or more layers ofwoven fabrics be secured together. Conventionally, this may be done byproviding the woven fabrics separately and then combining them toproduce a multi-layer structure. For example, various fabric layers maybe laid up and then joined together by resin. However, there are aseveral disadvantages to this technique. Firstly, since the wovenfabrics are manufactured separately, this tends to result in higherassociated costs. Furthermore, there may be issues related to thecompatibility of the added resin to the fabric, or various types ofballistic threats which it might be subject to. Finally, there tend tobe increased labor costs associated with laying up the layers of fabric.

In other known fabrics, multiple layers of woven fabric may be stitchedtogether after being manufactured as separate layers. However, theretends to be a number of drawbacks with stitching layers together. Sincestitched fabrics use needles that penetrate through the layers of yarn,gaps may be formed where the stitches are provided. Furthermore, thepenetration of the needles may cause damage to the yarns. Both of theseresults are generally undesirable.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings included herewith are for illustrating various examples ofarticles, methods, and apparatuses of the present specification and arenot intended to limit the scope of what is taught in any way. In thedrawings:

FIG. 1 is an overhead perspective view of a multi-layer woven fabricaccording to one embodiment;

FIG. 2 is a cross-sectional side view of the multi-layer woven fabric ofFIG. 1;

FIG. 3A is a photo of a multi-layer fabric according to anotherembodiment;

FIG. 3B is a close-up view of the photo of FIG. 3A;

FIG. 4 is a photo of a multi-layer fabric according to yet anotherembodiment having an offset weave;

FIG. 5 is a flowchart illustrating a method of manufacturing a wovenmulti-layer fabric according to another embodiment;

FIG. 6 is a cross-sectional side view of a multi-layer fabric having anoffset weave according to another embodiment;

FIG. 7 is a cross-sectional side view of a multi-layer fabric having anoffset weave according to another embodiment;

FIG. 8 is a photo of a multi-layer fabric having a plain weave and satinweave checker pattern according to yet another embodiment;

FIG. 9 is a photo of a multi-layer fabric having a plain weave and satinweave checker pattern according to yet another embodiment;

FIG. 10 is a photo of a multi-layer fabric having a plain weave (thebottom layer) and satin weave (the top layer) according to yet anotherembodiment;

FIG. 11 is a photo of a multi-layer fabric having a plain weave (the toplayer) and satin weave (the bottom layer) according to yet anotherembodiment;

FIG. 12 is a photo of a multi-layer fabric having two satin weave layersaccording to yet another embodiment;

FIG. 13 is a cross section side view of a multi-layer woven fabric, inaccordance with a further embodiment;

FIG. 14 is a perspective view of the multi-layer woven fabric of FIG.13;

FIG. 15 is a photo of a multi-layer woven fabric having securing yarnsin different directions; and

FIG. 16 is a flow chart of a method of manufacturing a woven multi-layerfabric according to a further embodiment.

DETAILED DESCRIPTION

Generally illustrated in FIGS. 1 and 2 is a multi-layer fabric 10according to one embodiment.

The fabric 10 has a first (or upper) woven layer indicated generally as11. The upper woven layer 11 includes first (or upper) warp yarns 12 andfirst (or upper) weft yarns 14 (e.g. 14 a, 14 b, 14 c, 14 d) that areinterwoven together to form the first or upper woven layer 11. The firstwarp yarns 12 and first weft yarns 14 in the upper woven layer 11 arecrimped, in the sense that each first yarn 12, 14 is bent around theother first yarns 12, 14 at crossover points or nodes to provide aninterlocking or interwoven structure.

The fabric 10 also has a second (or lower) woven layer indicatedgenerally as 13. The lower woven layer 13 includes second (or lower)warp yarns 15 and second (or lower) weft yarns 17 (e.g. 17 a, 17 b, 17c, 17 d) that are interwoven together to form the second or lower wovenlayer 13. The second warp yarns 15 and second weft yarns 17 in thesecond layer 13 are crimped, in the sense that each second yarn 15, 17is bent around the other yarns 15, 17 at crossover points or nodes toprovide an interwoven structure.

It will be appreciated that the terms “upper” and “lower” as used hereinare used for convenience only, and the actual relative positions of thefirst or upper woven layer 11 and the second or lower woven layer 13 maybe varied.

Generally the yarns of one layer are not interwoven with the yarns ofanother layer because such interweaving tends to increase the degree ofcrimp for the yarn in relation to rest of the yarns in the fabric, whichcan create ballistic weak points. In particular, the first or upperyarns 12, 14 are not interwoven with the second or lower yarns 15, 17,and vice versa. Instead, as shown, the first or upper layer 11 andsecond or lower layer 13 are secured together by one or more securingyarns 22. The securing yarns 22 are interwoven with at least some of theupper yarns 12, 14 and some of the lower yarns 15, 17 so as to securethe upper and lower layers 11, 13 together.

The securing yarns 22 generally form part of the woven fabric 10. Inparticular, the woven fabric 10 is formed by interweaving the securingyarns 22 with the warp yarns 12, 15 and weft yarns 14, 17 as the fabric10 is formed. Therefore, the upper and lower woven layers 11, 13 can besecured together without the need for stitching, resin or othermechanisms to join the woven layers 11, 13 together.

In this manner, a fabric 10 having two (or more) woven layers 11, 13 canbe manufactured as a unified construction, without the need for joiningtwo different fabric layers together after being formed individually.

Manufacturing the fabric as a unified construction also tends to providea lower crimp level for each layer, which tends to maintain or improvepotential ballistic performance of the individual layers while achievingadditional advantages associated with securing the layers together, suchas higher integrity, enhanced trauma and overall ballistic performanceas well as manufacturing advantages.

As shown, in some embodiments the securing yarns 22 may be aligned withthe warp or weft yarns. For example, the securing yarns 22 may begenerally parallel to or aligned with the warp yarns 12, 15 andgenerally perpendicular to the weft yarns 14, 17. In other embodiments,the securing yarns 22 may be generally parallel to or aligned with theweft yarns 14, 17 and generally perpendicular to the warp yarns 12, 15.In yet other embodiments (e.g. as shown in FIG. 3), securing yarns 22may be provided in both the warp and weft directions (e.g. in a checkerpattern) with at least some securing yarns 22 parallel to the warp yarns12, 15 while at least some other securing yarns 22 are parallel to theweft yarns 14, 17.

Turning now specifically to FIG. 2, illustrated therein is across-sectional side view of the woven multi-layer fabric 10. As shown,(from left to right on FIG. 2) one of the securing yarns 22 extends fromabove the upper layer 11 and passes underneath a first lower weft yarn17 a (of the lower weft yarns 17), then over a second upper weft yarn 14b (of the upper weft yarns 14, and generally next to or adjacent thefirst lower weft yarn 17 a), then underneath a third lower weft yarn 17c (generally next to or adjacent the second upper weft yarn 14 b), andthen above a fourth upper weft yarn 14 d (generally next to or adjacentthe third lower weft yarn 17 c) and then extends below the lower layer13. In this manner the securing yarn 22 tends to secure the upper weftyarns 14 and the lower weft yarns 17 together, thus joining the firstwoven layer 11 and the second woven layer 13.

While the illustrated embodiment shows a securing yarn extending overand under one weft yarn at a time, in other embodiments, the securingyarns may extend over or under more than one weft yarn at a time. Forexample, the securing yarns may be woven underneath two weft yarns, andthen above five upper weft yarns adjacent the lower weft yarns.Accordingly, the securing yarns may be woven underneath at least onelower weft yarn, and then above at least one upper weft yarn adjacentthe at least one lower weft yarn.

In some embodiments, one or more of the warp yarns 12, 15 and/or weftyarns 14, 17 could be used in addition to, or in place of, one or moresecuring yarns 22 for holding the two or more layers together. Forexample, one or more the of the warp yarns 12, 15 and/or the weft yarns14, 17 could be interwoven along a path similar to the path of thesecuring yarn 22 as shown in FIG. 2 to secure the first layer 11 to thesecond layer 13.

Each of the warp yarns 12, 15 and weft yarns 14, 17 and securing yarns22 may include a plurality of fibers or filaments of one or morematerials as will be described in greater detail below.

In some embodiments, the selection and arrangement of the securing yarns22 may be varied to obtain desired performance of the fabric 10. Forexample, the size, ratio and/or spacing of securing yarns 22 may bedifferent in different embodiments of the fabric 10.

In some embodiments, a plurality of securing yarns 22 could be spacedapart from each other by a distance of between one inch and threeinches. In other embodiments, securing yarns 22 may be spaced apart by adistance of less than one inch. In yet other embodiments, securing yarnsmay be spaced apart by a distance of more than three inches.

The ratio between securing yarns 22 and ballistic yarns (e.g. warp yarns12, 15 and weft yarns 14, 17) as well as the spacing therebetween tendsto depend on the desired inter-layer stability (e.g. providing moresecuring yarns 22 and/or providing securing yarns 22 spaced closertogether tend to result in a more stable fabric 10) versus the degree ofinterference between the woven layers 11, 13 (e.g. more securing yarns22 tend to result in the woven portions deviating more from aconventional woven fabric, e.g. which may cause more distortion betweenthe woven fabric layers).

In some embodiments, the securing yarns 22 are made from a highelongation yarn, a low strength, and/or a low modulus yarn, as generallydescribed below.

In some embodiments, the warp yarns 12, 15 and weft yarns 14, 17 areballistic yarns. For example, the warp yarns 12, 15 and weft yarns 14,17 may be ballistic yarns having a tenacity of about 15 grams per denierand higher, and with a tensile modulus of at least about 400 grams perdenier.

Some examples of suitable yarns could include carbon, basalt and glassfibers. Other examples include aramid and copolymer aramid fibers(produced commercially by DuPont and Teijin under the trade namesKevlar®, Twaron®, and Technora®), extended chain polyethylene fibers(produced commercially by Honeywell, and DSM, under the trade namesSpectra®, and Dyneema®), polyethylene fibers and films produced bySynthetic Industries and sold under the trade name Tensylon®,poly(p-phenylene-2,6-benzobisoxa-zole) (PBO) (produced by Toyobo underthe commercial name Zylon®), and Liquid crystal polymers produced byKuraray under the trade name Vectran®. Other suitable yarns may also beused.

In some embodiments, the securing yarns 22 are generally ofsignificantly smaller denier than the warp yarns 12, 15 and/or weftyarns 14, 17 and may have significantly lower tenacities and tensilemoduli. As a result, the securing yarns 22 tend to greatly reduce oreliminate undesirable deflection or distortion of the first and secondlayers 11, 13. In particular, the securing yarn 22 may be substantiallycrimped while it may be desirable to have the layers 11, 13 be as flatas possible.

In some examples, the securing yarns 22 have a tenacity of less thanabout 10 grams per denier, and a tensile modulus of less than about 40grams per denier. In one example, the securing yarns 22 are made of a 78dtex Nylon, while the warp yarns 12, 15 and weft yarns 14, 17 may bemade of a 3000 denier aramid (e.g. Kevlar®).

In some examples, the denier of the securing yarns 22 may range frombetween about 20 denier (or less), to about 1000 denier, depending onthe size of the warp yarns 12, 15 and weft yarns 14, 17, and the desiredballistic applications.

In some alternative examples, the same yarn that is used in the wovenbody of either fabric layer may be used as a securing yarn to tie thetwo or more layers of fabric together (i.e., the warp and/or weft yarnscould be used as securing yarns).

In some embodiments, the securing yarns 22 may be generally of a muchsmaller size than the warp yarns 12, 15 and weft yarns 14, 17. Thediameter of the securing yarns 22 may be selected based on the moduliand strength parameters of the securing yarns 22. In some embodiments,where the securing yarns 22 are made of non-ballistic yarns (e.g. Nylon,etc.), it may be desirable that the securing yarns 22 be high elongationyarns that are as stretchy as possible and as small as possible.

In some examples, the securing yarns 22 may be selected from a widerange of fibers. Some suitable example fibers include natural fibers,such as cotton, wool, sisal, linen, jute and silk. Other suitable fibersinclude manmade or synthetic fibers and filaments, such as regeneratedcellulose, rayon, polynosic rayon and cellulose esters, synthetic fibersand filaments, such as acrylics, polyacrylonitrile, modacrylics such asacrylonitrile-vinyl chloride copolymers, polyamides, for example,polyhexamethylene adipamide (nylon 66), polycaproamide (nylon 6),polyundecanoamide (nylon 11), polyolefin, for example, polyethylene andpolypropylene, polyester, for example, polyethylene terephthalate,rubber and synthetic rubber and saran. Glass, carbon or any other highperformance fiber may also be used.

Staple yarns may also be used and may include any of the above fibers,low denier staple yarns or any combination of these yarns. Staple yarns,by the discontinuous nature of their filaments that form the yarn, tendto have much lower tensile and modulus properties as opposed to yarnscomposed of continuous filaments.

The performance of the fabric 10 is generally a function of theproperties of the securing yarns 22 and the warp yarns 12, 15 and weftyarns 14, 17. In ballistic fabrics, maximizing the amount of theballistic fibres (e.g. the warp yarns 12, 15 and the weft yarns 14, 17)in a given volume tends to be beneficial, as higher fibre to volumeratio fraction generally signifies improved ballistic properties.Therefore, in some examples it may be desirable that the securing yarns22 have a denier that is as low as practical while still being able toweave the fabric 10.

In the fabric 10, it may be desirable to minimize the weight of thesecuring yarns 22 as a percentage of the total weight of the fabric 10,since the securing yarns 22 may not contribute as much to the strengthof the fabric 10 as the ballistic yarns (e.g. the warp yarns 12, 15 andthe weft yarns 14, 17). Conversely, an increased quantity of securingyarns 22 may result in a more durable, stable fabric 10; however, thefabric 10 may tend to be heavier.

In some examples, the securing yarns 22 may be selected to have thelowest denier, and the lowest strength as practical that can be wovenbetween the layers, and that satisfy the requirements for a particularballistic application.

In some embodiments, two or more fabrics 10 may be joined together toform a ballistic member having four or more woven layers (e.g. twofabrics 10 may be joined using a resin, film or other suitabletechniques to form a fabric that has four woven layers).

The fabric 10 may also be fabricated into a prepreg using a film or awet resin. Depending on the application, the film or resin may beapplied to one side of the fabric 10, the fabric 10 may be totallyimpregnated with a resin, or the film may be worked into the fabric 10.In some examples, the film or resin may be a thermoplastic or athermoset resin. Generally, any resin or film that can be used to createa prepreg may be used with this fabric 10. In some embodiments, two ormore layers of fabric 10 may be laminated together to further increasethe number of layers.

In some embodiments, three or more woven layers may be secured togetherto form a fabric using one or more securing yarns that are interwoven asthe fabric is being made.

Turning now to FIGS. 3A and 3B, illustrated therein is a fabric 110according to another embodiment. The fabric 110 has a first woven layer111 (e.g. having first interwoven warp and weft yarns) and a secondwoven layer 113 (e.g. having second interwoven warp and weft yarns). Thefirst and second layers 111, 113 are secured together by securing yarns122 that are interwoven with the first and second warp and weft yarns asthe fabric 110 is woven together.

Referring now to the close up of FIG. 3B, the fabric 110 is being pulledapart to reveal the securing yarns 122 in more detail. In particular,first securing yarns 122 a are oriented in a first direction (e.g. thewarp direction) while second securing yarns 122 b are oriented in asecond direction (e.g. the weft direction).

In one exemplary embodiment, a multi-layer woven fabric according toFIGS. 3A and 3B was created and tested in a ballistic 9 mm V50 test. Inparticular, a woven multi-layer fabric as generally described hereinmade of 3360 dtex aramid was compared to a traditional fabric withseparate layers laminated together using a resin. The V50 ballistic testfor these fabrics were conducted in a standard setting for a 16″×16″pack using a 9 mm Remington and at 0.75 lb/ft2 for both samples, withthe following results:

Fabric Ballistic Pack Ballistic Areal Density Areal Density 9 mm V50Product Description Dry (g/m2) lb/ft2 Kg/m2 ft/s m/s Conventional Aramid606 0.75 3.64 1112 339 3360 dtex 1 × 1 Plain, 2 layer laminate New WovenMulti-layer 1212 0.75 3.64 1125 343 Aramid 3360 dtex 2L Plain, 2 layerlaminate

As shown, the woven multi-layer fabric tends to provide similarperformance as a conventional fabric while providing at least some ofthe advantages as generally described herein. For example, the newmulti-layer fabric has gone through about half the number of processingsteps in comparison to the conventional fabric, which is advantageousfor both performance and cost.

In some embodiments, the multi-layer fabric might be used with a resin.If the fabric has high adhesion to the resin, the securing yarn candissipate energy by breaking during the ballistic event while the resinkeeps the other layers together and prevents trauma.

Turning now to FIG. 4, illustrated therein is a fabric 210 according toanother embodiment in which the fabric 210 has an offset weave. Inparticular, the fabric 210 has two separate layers: namely a first orupper layer 211 and a second or lower layer (not shown). In this fabric210, the upper and lower warps and wefts are offset. In particular, theupper warp yarns are not sitting on top of the lower warp yarns, butrather are sitting beside each other (e.g. are at least slightlyoffset), and the upper weft yarns are not sitting on top of the lowerweft yarns, but rather are sitting beside each other (e.g. are at leastslightly offset). This offset weave generally provides the fabric 210with more room to spread out, resulting is less squishing or crimping ofthe fabric 210.

The offset design also tends to improve ballistic performance byreducing the number and/or size of openings between yarns in the fabricbecause the yarns of one layer cover openings in the adjacent layer, asdescribed below.

In some ballistic applications, it is sometimes desirable to lower thecover factor of the fabric (e.g. by spacing apart yarns and providingopenings therebetween) in order to increase the number of fabric layersin a pack for a given areal density. The increased number of fabriclayers tends to enhance the ballistic V50 performance. However, there isa limit to the increase in performance because having a cover factorthat is too low results in an open construction, which tends to increasethe bullet penetration during a ballistic event and hence lowers theballistic resistance. The offset design described above tends to enhanceballistic performance for a given yarn size and ballistic areal densityby providing the layering effect while covering the openings in eachlayer with the yarns of the adjacent layer as the two layers areinterwoven in an offset layering pattern.

In some embodiments, some of the warp yarns and/or weft yarns may atleast partially overlap, which the inventor believes may tend toincrease the ballistic performance.

As shown, the first layer 211 and second layer are secured together by aplurality of first securing yarns 222 a and a plurality of second 222 b(generally similar to the securing yarns 22 as described above) that aregenerally perpendicular to each other and which are arranged in an arrayor pattern. For example, the first securing yarns 222 a may be orientedin a first direction (e.g. the warp direction), while the secondsecuring yarns 222 b may be oriented in a second direction (e.g. theweft direction).

As shown, the first securing yarns 222 a may be separated from eachother by a first spacing T, while the second securing yarns 222 b may beseparated from each other by a second spacing S. The first and secondspacings T, S may be similar or different. Generally, the spacings T, Smay be selected so as to obtain desired properties for the fabric 210.

In some embodiments, the first spacing T may be between one inch andthree inches. In other embodiments, the first spacing T may be less thanone inch, or more than three inches.

In some embodiments, the second spacing S may be between one inch andthree inches. In other embodiments, the second spacing S may be lessthan one inch, or more than three inches.

In some embodiments, the layers of fabric may be secured using securingyarns that extend in only one direction (e.g. the weft direction only).

Turning now to FIG. 5, illustrated therein is a method 100 of forming amulti-layer woven fabric according to one embodiment.

At step 102, warp yarns are provided. For example, first warp yarns 12and second warp yarns 15 may be provided on a loom or weaving machine(e.g. standard 2D weaving looms, including rapier, shuttle, air jet andwater jet looms).

At step 104, weft yarns are interwoven with the warp yarns to form atleast two woven layers (e.g. a first woven layer and a second wovenlayer). For example, the first weft yarns 14 could be interwoven withthe first warp yarns 12 by alternatively moving the first warp yarns 12up and down and passing a shuttle with the first weft yarns 14therebetween, as will generally be understood. Similarly, the secondwarp yarns 15 could be interwoven with the second weft yarns 17 to formthe second woven layer 13.

At step 106, the securing yarns are interwoven with the warp yarnsand/or the weft yarns as the fabric is being made (e.g. as the weftyarns and warp yarns are being woven together) to secure the first andsecond woven layers together. For example, the securing yarns 22 may bealternatively interwoven with the first and second warp yarns 12, 15 byselectively moving the warp yarns 12, 15 up and down and passing ashuttle with the securing yarns 22 therethrough as the warp yarns 12, 15and weft yarns 15, 17 are being woven together.

It will be appreciated that the steps 102, 104 and 106 of the method 110generally do not have to be done in a specific order and that the orderas listed is in no way meant to be limiting.

Turning now to FIG. 6, illustrated therein is another fabric 310according to another embodiment having an upper layer 311 that is offsetfrom the lower layer 313. For example, the fabric 310 may be similar tothe fabric 210 described previously.

The upper woven layer 311 includes warp yarns 312 and upper weft yarns314 (e.g. 314 a, 314 b, 314 c, 314 d) that are interwoven together toform the first or upper woven layer 311. The lower woven layer 313includes lower warp yarns 315 and lower weft yarns 317 (e.g. 317 a, 317b, 317 c, 317 d) that are interwoven together to form the second orlower woven layer 313. The upper and lower woven layers 311, 313 aresecured together using one or more securing yarns 322 generally asdescribed previously.

As shown, the upper weft yarns 314 and lower weft yarns 317 are offsetso that, for example, the first upper weft yarn 314 a overlaps the firstlower weft yarn 317 a by an overlap amount P. Accordingly, the securingyarn 322 tends to be less crimped and more spread out (as compared tothe more compact path of the securing yarn 22 described above).

In some embodiments, the overlap amount P is between 10% and 95%. Inother embodiments, the overlap amount P is between 30% and 70%. In otherembodiments, the overlap amount is around 50%.

Turning now to FIG. 7, illustrated therein is a fabric 410 according toyet another embodiment. Fabric 410 has an upper layer 411 that is offsetfrom the lower layer 413.

The upper woven layer 411 includes warp yarns 412 and upper weft yarns414 (e.g. 414 a, 414 b, 414 c, 414 d) that are interwoven together toform the first or upper woven layer 411. The lower woven layer 413includes lower warp yarns 415 and lower weft yarns 417 (e.g. 417 a, 417b, 417 c, 417 d) that are interwoven together to form the second orlower woven layer 413. The upper and lower woven layers 411, 413 aresecured together using one or more securing yarns 422 generally asdescribed above.

As shown, the upper weft yarns 414 and lower weft yarns 417 are offsetsimilar to the fabric 310, so that, for example, the first upper weftyarn 414 a overlaps the first lower weft yarn 417 a by an overlap amountP. In this embodiment, the upper weft yarns 414 and lower weft yarns 417are generally more evenly spaced apart by the overlap distance P.

Turning now to FIG. 8, illustrated therein is a multi-lawyer wovenfabric 510 according to another embodiment. The fabric 510 generallyincludes an upper woven layer 511 and lower woven layer 513 securedtogether using first securing yarns 522 a and second securing yarns 522b generally as described previously. In this embodiment, the upper wovenlayer 511 and lower woven layer 513 each have a “checkered” pattern madeup of adjacent plain woven portions 525 (e.g. portions of the layers511, 513 with a plain weave) and satin woven portions 527 (e.g. portionsof the layers 511, 513 with a satin weave). These types of woven layersmay be referred to as Platin™ and are described more generally in PCTInternational Patent Application Publication Numbers WO2009153120 andWO2009153121.

In this embodiment, the plain woven portions 525 and satin wovenportions of the upper and lower layers 511, 513 are aligned. Forexample, as shown a first plain woven portion 525 a on the upper layer511 is aligned with and positioned above a second plain woven portion525 b on the lower layer.

Turning now to FIG. 9 illustrated therein is a multi-lawyer woven fabric610 according to another embodiment. The fabric 610 is similar to fabric510 and generally includes an upper woven layer 611 and lower wovenlayer 613 secured together using first securing yarns 622 a and secondsecuring yarns 622 b generally as described previously. However, in thisembodiments the “checked” plain woven and satin portions are staggeredwith respect to each other. For example, as shown a first plain wovenportion 625 a on the upper layer 611 is aligned with and positionedabove a second satin woven portion 627 b on the lower layer 613.

While the embodiments of FIGS. 8 and 9 have Platin™ layers arranged sothat the woven portions and satin portions are either matching oropposite, in some embodiments, the Platin™ layers may be arranged in arandom design such that the woven portions and satin portions of eachlayer are offset from each other, opposed to being aligned in eithermatching or opposite patterns.

Multi-layer woven fabrics made with Platin™, and as described above,were created and tested in a ballistic 9 mm V50 test, with the followingresults:

Ballistic Pack Areal Density Ballistic 9 mm V50 Product Descriptionlb/ft2 Kg/m2 ft/s m/s 2 layer Platin with 1.1 5.4 1505 459 matchingpatterns 2 layer Platin with 1.1 5.4 1496 456 opposite patterns 2 layerPlatin with 1.1 5.4 1470 448 random design

As show, the performance of the 2 layer Platin fabric with matchingpatterns performed better than the other two fabrics.

In another exemplary embodiment, a multi-layer woven fabric with offsetwoven layers was created and tested in a ballistic 9 mm test as well asa 0.22 CAL 17 grain FSP test and compared to a plain fabric. The offsetwoven layers were secured together using securing yarns aligned with theweft yarns only. The securing yarns were spaced separated by a spacingof about a ¼ of an inch. The ballistic tests for these fabrics wereconducted in a standard setting for a 16″×16″ pack using a 9 mmRemington and a 0.22 CAL FSP at an areal density of 1.1 lb/ft2 for bothsamples, with the following results:

Areal Areal Fabric, all Density (of Density (of 17 grain 9 mm greige,aramid # of the layer) the pack) @1.1 @1.1 930 dtex layers g/m² Psf psfpsf Offset 23 233 1.10 654 521 Plain Fabric 26 207 1.11 622 502

The performance in the 9 mm and 0.22 CAL FSP tests were both improved.Furthermore, the performance in the 0.22 CAL FSP test was improved withthe offset fabric by 33 feet, an increase of approximately 5.3%.

The new fabric with offset woven layers had a higher performance in bothtests with fewer layers of fabric. This is despite the conventionalunderstanding that a fabric having a lower cover factor and more layersof fabric for a given areal density should perform better. The inventorbelieves that the increased performance is due to the offset design, inwhich the coverage for each yarn within the fabric structure ismaximized by having each direction yarn (warp or weft) sitting at twolevels with overlaps.

While the exemplary embodiment tested utilized securing yarns alignedwith the weft yarns and spaced apart by about a ¼ of an inch, in otherembodiments, the securing yarns may be aligned with the warp yarnsand/or the weft yarns, and may be separated by a spacing of less thanthree inches.

Additional Example

According to another example, a multilayer fabric was woven at about100% cover factor for each of the layers in a two layer woven fabric.The fabric yarn size was 550 dtex, which is higher than yarn sizescommonly used in spike protection.

Lower yarn sizes tend to be advantageous is spike resistance. Inparticular, spike resistance tends to deteriorate as the yarn sizesincrease to a point that the weight disadvantage of additional fabriclayers for higher denier yarns prohibits the viability of the productfrom both a weight and cost point of view.

However, in this example, the 550 dtex yarn size (which is not a commonyarn size used in traditional spike applications) was explored and madeinto a woven fabric according to the teachings herein. The scouredfabric layers were then tested at Barrday's internal lab and inaccordance with the ‘National Institute of Justice (NIJ) Standard0115.00-Stab Resistance of Personal Body Armor’. These test protocolsand test conditions are defined in the NIJ spec, as well as thedefinitions for various energy levels.

The following table summarizes the test results for this fabric, andindicate that this fabric is a viable solution for spike resistance eventhough it is at a higher yarn size of 550 dtex.

NIJ test results for 550 dtex Description Dry W NIJ Spike level Layer#AD(psf) 550 dtex SOS45 400 L1E2 4 0.33 L2E2 6 0.49 L3E2 6 0.49

The fabrics described herein may generally be used in any combinationwith the materials listed above and may replace any one material orcombination of materials in an existing ballistic fabric. In addition,the fabrics described herein may be laminated together or laminated withfilms to produce ballistic elements for various applications, includingsoft armor applications, hard armor applications, and rigid and/orsemi-rigid applications. The proportions of each material selected andthe design of the ballistic elements may vary depending on the intendedapplication (i.e. particular specifications for military or policeapplications).

Generally, the multi-layer fabrics described herein utilize a uniquetechnique to secure fabric layers together and limit the use of extrastitching and resin application unless desired for providing particularproperties.

Turning now to FIG. 10, illustrated therein is a multi-layer fabrichaving a plain weave (the bottom layer) and satin weave (the top layer)according to yet another embodiment.

Similarly, FIG. 11 shows a multi-layer fabric having a plain weave (thetop layer) and satin weave (the bottom layer) according to yet anotherembodiment.

FIG. 12 shows a multi-layer fabric having two satin weave layersaccording to yet another embodiment.

FIGS. 13 and 14 show a multi-layer fabric 700 in accordance with afurther embodiment. The multi-layer woven fabric 700 includes aplurality of fabric assemblies: a first fabric assembly 702 and a secondfabric assembly 718. While FIGS. 13 and 14 show two fabric assemblies,three, four, or more assemblies may be used to make the multi-layerwoven fabric, as desired. The first and second fabric assemblies 702,718 may be those described with reference to FIGS. 1, 2, 6, and 7.

The first fabric assembly 702 includes a plurality of woven lawyers(first upper woven layer 704 and first lower woven layer 710) and afirst securing yarn 716. In an embodiment, the first fabric assembly 702may include two layers (as shown in FIGS. 13 and 14), three layers, fourlayers, or more layers, as desired.

The first upper woven layer 704 has first upper weft yarns 706 and firstupper warp yarns 708 that are interwoven together to form the firstupper woven layer 704. The first lower woven layer 710 has first lowerweft yarns 712 and first lower warp yarns 714 that are interwoventogether to form the first lower woven layer 710.

The first securing yarn 716 is interwoven with at least some of thefirst upper yarns 706, 708 and some of the first lower yarns 712, 714 soas to secure the first upper woven layer 706 and first lower wovenlayers 710. The first securing yarn 716 is interwoven with the firstyarns 706, 708, 712, 714 in a first direction, for example the warpdirection.

The second fabric assembly 718 is layered with and may be secured to thefirst fabric assembly 702. Similar to the first fabric assembly 702, thesecond fabric assembly 718 includes a plurality of woven layers (secondupper woven layer 720 and second lower woven layer 726) and a secondsecuring yarn 732.

The second upper woven layer 720 has second upper warp yarns 722 andsecond upper weft yarns 724 that are interwoven together to form thesecond upper woven layer 720. The second lower woven layer 726 hassecond lower warp yarns 728 and second lower weft yarns 730 that areinterwoven together to form the second lower woven layer 726.

The second securing yarn 732 is interwoven with at least some of thesecond upper yarns 722, 724 and some of the second lower yarns 728, 730so as to secure the second upper woven layers 720 and second lower wovenlayers 726 together. The second securing yarn 732 is interwoven with thesecond yarns 722, 724, 728, 730 in a second direction.

The first fabric assembly 702 and the second fabric assembly 718 areassembled such that the second securing yarn 732 runs in a differentdirection from the first securing yarn 716. In an embodiment, the firstsecuring yarn 716 runs substantially perpendicularly (e.g. 90 degrees)to the second securing yarn 732.

In an embodiment, the first fabric assembly 702 and the second fabricassembly 718 are assembled together by a stitching yarn, for example, ason the periphery during assembly. In a further embodiment, the first andsecond fabric assemblies 702, 718 are assembled with further fabriclayers.

The multi-layer fabric 700 may have increased strength as the securingyarns 716, 732 provide securing strength in different directions.

FIG. 15 shows a 600 d Kevlar KM2 PLUS multi-layer fabric 800, inaccordance with an embodiment. The multi-layer fabric 800 has a firstfabric assembly 802 and second fabric assembly 804 with first and secondsets of securing yarns 806, 808 running in different directions. Each ofthe first and second fabric assemblies 802, 804 have four fabric layers.The first fabric assembly 802 has four fabric layers 810, 812, 814, 816and securing yarns 806 travelling left-right. The second fabric assembly804 as four fabric layers 818, 820, 822, 824 with securing yarns 808traveling top-bottom.

FIG. 16 shows a method 900 for producing a multi-layer fabric, inaccordance with an embodiment. The method 900 may produce themulti-layer fabric 700, 800 shown in FIGS. 13, 14, and 15.

At 902, a fabric assembly is produced having a securing yarn running ina single direction (for example the fabric assembly as described withreference to FIG. 1, 2, 6, or 7).

At 904, the fabric assembly is separated (e.g. by cutting) crosswise(e.g. perpendicularly to the securing yarn) into first and second fabricassembly sections (e.g. 702, 718 or 802, 804).

At 906, the first fabric assembly (702, 802) is rotated (e.g. by 90degrees) to the second fabric assembly (718, 804).

At 908, the first fabric assembly (702, 802) is assembled with thesecond fabric assembly (718, 804).

As the first and second fabric assemblies (702, 718, 802, 804) may beproduced in a single-step production, costs may be reduced as singledirectional stitching of the securing yarn is performed.

Table A shows trauma for two Kevlar KM2 PLUS test materials measured inaccordance with NIJ ballistic standard 0101.06 at velocities of1400-1450 ft/sec or 427-442 m/sec and recorded in mm. Table A shows theresults for a “standard 0 degree” multi-layer fabric having eight fabricassemblies of four layers with securing yarns running through the fourlayers and the securing yarns running parallel to each other for alleight fabric assemblies. Table A also shows the results of the same testfor a “0-90 degree alternating layer” multi-layer fabric that has eightfabric assemblies of four layers with securing yarns alternatingdirection by 90 degrees after each layer.

TABLE A Samples Shot #1 Shot #2 Shot #3 Shot #4 Average(mm) Standard 0degree 34 34 38 42 37 0-90 degree 30 27 34 27 29.5 alternating layer

Table B shows trauma for four Kevlar KM2 PLUS test materials measured inaccordance with NIJ ballistic standard 0101.06 at velocities of1400-1450 ft/sec or 427-442 m/sec and recorded in mm. Table B shows theresults for a “standard 0 degree” multi-layer fabric (of a differentmaterial to that of Table A) having eight fabric assemblies of fourlayers with securing yarns running through the four layers and thesecuring yarns running parallel to each other for all eight assemblies.

Table B also shows the results for a “0-90 degree every 2-4-2”multi-layer fabric having eight fabric assemblies of four layers. Themulti-layer fabric is arranged such that the securing yarns in the firsttwo fabrics are parallel, the securing yarns in the third through sixthfabrics are perpendicular to the securing yarns in the first two fabricassemblies and the securing yarns in the seventh and eight fabricassemblies are parallel to the securing yarns in the first two fabricassemblies (and perpendicular to the securing yarns in the third throughsixth layers).

Table B also shows the results for a “0-90 degree every 3-2-3”multi-layer fabric having eight fabric assemblies of four layers. Themulti-layer fabric is arranged such that the securing yarns in the firstthree fabrics are parallel, the securing yarns in the fourth and fifthfabrics are perpendicular to the first three fabric assemblies, and thesecuring yarns in the sixth through eighth fabric assemblies areparallel to the securing yarns in the first three fabric assemblies (andperpendicular to the securing yarns in the fourth and fifth layers).

TABLE B Samples Shot #1 Shot #2 Shot #3 Shot #4 Average(mm) Standard 0degree 36 41 36 35 37.0 0-90 degree every 28 35 29 30 30.5 2-4-2 layers0-90 degree every 30 34 35 32 32.8 3-2-3 layers

As can be seen from Tables A and B, when the securing yarn directionsare alternated, the average trauma depth is decreased indicating astronger fabric. Further, the “0-90 degree every 2-4-2 layers” fabricmay exhibit improved trauma capacity over the “0-90 degree every 3-2-3layers” fabric.

While some improvements may be achievable through post process sewing ofthe components in a final assembly (e.g. a vest package), in the method900 there may not be additional post processing such as post processsewing that may result in damaging the yarns in the fabric as well asmaking the pack much more stiff and not as comfortable to wear.Alternating layer designs as described with reference to FIGS. 13-16 mayimprove the trauma performance while maintaining the V50 performance. Incontrast, where there is post process assembly, Trauma enhancement maybe achieved at the expense of lowering V50.

In some embodiments, one or more woven multi-layer fabrics as generallydescribed herein may be suitable for other types of threats, such asstab or spike threats. For example, some woven multi-layer fabrics maybe suitable against stab or spike threats in addition to (or as analternative to) being effective against ballistic threats.

In particular, there is a need, especially in fields like lawenforcement and for use in correctional facilities (i.e., jails,prisons, etc.), for protective clothing that provides some protectionfor a wearer against penetration of a variety of dangerous instruments,such as blades, picks, shanks, awls, and the like.

Some protective clothing is designed to be resistant to either stabbingmaterials (i.e., ice picks, knives and the like), or ballistic threats,but not both. In some circumstances, however, it may not be practical orsafe to be protected from only one of these threats. Nor may itbepractical to wear multiple layers of protective wear, with eachindividual layer is designed for a different threat, since this may bebulky or uncomfortable.

Several known approaches to protect against both stabbing and ballisticthreats are problematic. One typical prior art approach is to simply addstab resistant materials to ballistic resistant fabrics. For example, astab resistant metal sheet (such as a titanium sheet) could simply besecured to a ballistic resistant fabric. However, such constructionstend to be bulky and may be uncomfortable to the point of beingimpractical.

According to some embodiments as described herein, at least some levelof protection against non-ballistic threats may be provided by somewoven multi-layer fabrics. For instance, the properties of the wovenmulti-layer fabric (i.e. yarn types) as well as the spacing andarrangement of weaving patterns may be selected to provide for at leastsome protection against stab and/or spike threats.

In some cases, these same fabrics may also provide for ballisticprotection, although this is not necessarily required. In some examples,the securing yarns may be made of non-ballistic yarns (i.e., Nylon),while the warp yarns and weft yarns may be made of aramid (e.g.Kevlar®). In other examples, the securing yarns and the warp yarns andweft yarns may be made of any suitable combination of ballistic ornon-ballistic yarns.

In some embodiments, the cover factor of each layer of the wovenmulti-layer fabric may be selected so as to inhibit penetration bynon-ballistic threats, such as spikes and blades. For example, in oneembodiment, a woven multi-layer fabric may be provided which has a coverfactor between 70% and 130% for at least one of the layers of fabric. Inanother embodiment, a woven multi-layer fabric may be provided which hasa cover factor between 80% and 120% for at least one of the layers offabric. In another embodiment, a woven multi-layer fabric may beprovided which has a cover factor between 90% and 110% for at least oneof the layers of fabric. In yet another embodiment, a woven multi-layerfabric may be provided which has a cover factor around 100% for at leastone of the layers of fabric. In yet other embodiments, both layers of awoven multi-layer fabric with two layers will have a cover factor ofbetween 90 and 110%.

Selecting a cover factor in this manner will tend to encouragepenetration resistance of the fabric.

In some embodiments, the desired cover factor might be achievedaccording to particular weaving patterns and techniques.

In some embodiments, the properties of the yarns and/or processesapplied to the fabric could be selected to promote a desired coverfactor for each layer. For instance, in some embodiments, after thefabric has been woven, the fabric could be subjected to a treatmentprocess that encourages the securing yarns to shrink, which tends todraw the warp and weft yarns toward each other I the woven multi-layerfabric, thus encouraging higher cover factors.

In one specific example, securing yarns could be encouraged to shrink byup to 1%, up to 3%, more than 3%, or even up to 10%.

In some embodiments, once a woven multi-layer fabric has been woven, thefabric may be subjected to a process to increase the penetrationresistance of the fabric. For example, this may be done by densifyingthe fabric, in some cases through a minimum of at least about 1%shrinkage. Shrinkage of the fabric during densification tends to engagea greater number of fibers in a particular area and increase thepenetration resistance of the fabric.

In other cases, penetration resistance may be increased by fibrillatingthe yarns of the fabric, or using other techniques.

As described in detail above, in some embodiments, some of the warpyarns and/or weft yarns of the different layers of a woven multi-layerfabric may at least partially overlap. In some embodiments, the overlapamount P of the woven multi-layer fabric may be selected so as encouragepenetration resistance to non-ballistic threats. For example, theoverlap amount P may be between 10% and 95%. In other embodiments, theoverlap amount P is between 30% and 70%. In other embodiments, theoverlap amount is around 50%.

In some embodiments that may be well suited for non-ballistic threats,the overlap amount P may be between about 90 and 95%. In some otherembodiments that may be well suited for non-ballistic threats, theoverlap amount P may be above 95%. In some further embodiments, theoverlap amount P may be above 98%, or even 99%, or even approaching (orat) 100%.

Configuring the woven multi-layer fabrics in this manner (i.e.,adjusting the cover factor of the layers and/or the overlap amount P)may allow certain fabrics to be effective against non-ballistic threats.Moreover, some of these fabrics may be effective against both ballisticand non-ballistic threats, making them “multi-threat” fabrics.

While the above description provides examples of one or more fabrics,processes or apparatuses, it will be appreciated that other fabrics,processes or apparatuses may be within the scope of the presentdescription as interpreted by one of skill in the art.

1. A multi-layer woven fabric, comprising: a first fabric assemblycomprising: a first upper woven layer having first upper warp yarns andfirst upper weft yarns that are interwoven together to form the firstupper woven layer; a first lower woven layer having first lower warpyarns and first lower weft yarns that are interwoven together to formthe first lower woven layer; and a first securing yarn interwoven withat least some of the first upper yarns and some of the first lower yarnsso as to secure the first upper and first lower woven layers together;and a second fabric assembly layered with the fabric assembly, thesecond fabric assembly comprising: a second upper woven layer havingsecond upper warp yarns and second upper weft yarns that are interwoventogether to form the second upper woven layer; a second lower wovenlayer having second lower warp yarns and second lower weft yarns thatare interwoven together to form the second lower woven layer; and asecond securing yarn interwoven with at least some of the second upperyarns and some of the second lower yarns so as to secure the secondupper and second lower woven layers together, wherein the secondsecuring yarn runs in a different direction from the first securingyarn.
 2. The fabric of claim 1, wherein the first and second securingyarns run 90 degrees to each other.
 3. The fabric of claim 1, whereinthe first fabric assembly has four pairs of warp weft yarns secured bythe first securing yarns and wherein the second fabric assembly has fourpairs of warp weft yarns secured by the second securing yarns.
 4. Thefabric of claim 3, having six additional fabric assemblies.
 5. Thefabric of claim 4, wherein each of the fabric assemblies alternate insecuring yarn direction.
 6. The fabric of claim 4, wherein the fabricassemblies alternate in a two-four-two in the securing yarn direction.7. The fabric of claim 4, wherein the fabric assemblies alternate in athree-two-three in the securing yarn direction.
 8. The fabric of claim 1wherein at least some of the securing yarns are made of non-ballisticyarns.
 9. The fabric of claim 1 wherein at least some of the securingyarns are made of ballistic yarns.
 10. The fabric of claim 1 wherein atleast some of the warp yarns and weft yarns are made of ballistic yarns.11. The fabric of claim 1 wherein at least some of the warp yarns andweft yarns are made of non-ballistic yarns.
 12. The fabric of claim 1,wherein the spacing and arrangement of weaving patterns of the fabricare selected to provide for at least some protection againstnon-ballistic threats.
 13. The fabric of claim 1, wherein after thefabric has been woven, the fabric is subjected to a treatment processthat encourages the securing yarns to shrink, drawing the warp yarns andweft yarns towards each other.
 14. The fabric of claim 15, wherein thesecuring yarns are encouraged to shrink by up to 1%.
 15. The fabric ofclaim 15, wherein the securing yarns are encouraged to shrink by up to3%.
 16. The fabric of claim 15, wherein the securing yarns areencouraged to shrink by up more than 3%.
 17. The fabric of claim 15,wherein the securing yarns are encouraged to shrink by up to 10%. 18.The fabric of claim 1, wherein at least some of the upper weft yarns andlower weft yarns are offset from each other so as to overlap by between30% and 70%.
 19. The fabric of claim 1, wherein at least some of theupper yarns and lower yarns are offset from each other so as to overlapby between 10% and 95%.
 20. The fabric of claim 1, wherein at least someof the upper yarns and lower yarns are offset from each other so as tooverlap by more than 95%. 21.-37. (canceled)